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From: "christophm30 at gmail dot com" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/105314] New: ifcvt regression in noce_try_store_flag_mask Date: Tue, 19 Apr 2022 20:19:09 +0000 [thread overview] Message-ID: <bug-105314-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105314 Bug ID: 105314 Summary: ifcvt regression in noce_try_store_flag_mask Product: gcc Version: 12.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: tree-optimization Assignee: unassigned at gcc dot gnu.org Reporter: christophm30 at gmail dot com Target Milestone: --- The function noce_try_store_flag_mask() in ifcvt.cc converts "if (test) x = 0;" to "x &= -(test == 0);" (if costs permit that). Commit 3a7ba8fd (which was introduced a month ago to fix PR104960) triggers a regression so that the if-conversion can't be performed anymore. On RISC-V this manifests as follows: """ long func(long a, long b, long c) { if (c) a = 0; return a; } """ Old code: 0000000000000000 <func>: 0: 00163613 seqz a2,a2 4: 40c00633 neg a2,a2 8: 8d71 and a0,a0,a2 a: 8082 ret New (branching) code: 0000000000000000 <func>: 0: c211 beqz a2,4 <.L1> 2: 4501 li a0,0 0000000000000004 <.L1>: 4: 8082 ret Looking through the test suite, I could only find the file "gcc.target/arm/ifcvt-size-check.c" which should be affected by this regression as well. However, I haven't tested that.
next reply other threads:[~2022-04-19 20:19 UTC|newest] Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top 2022-04-19 20:19 christophm30 at gmail dot com [this message] 2022-04-19 20:23 ` [Bug tree-optimization/105314] " christophm30 at gmail dot com 2022-04-20 7:10 ` marxin at gcc dot gnu.org 2022-04-20 7:10 ` marxin at gcc dot gnu.org 2022-04-20 7:49 ` [Bug target/105314] " rguenth at gcc dot gnu.org 2022-04-22 9:48 ` [Bug target/105314] [12 Regression] " pinskia at gcc dot gnu.org 2022-04-25 15:45 ` [Bug rtl-optimization/105314] " jakub at gcc dot gnu.org 2022-04-25 22:34 ` ptomsich at gcc dot gnu.org 2022-04-25 22:40 ` christophm30 at gmail dot com 2022-04-25 22:47 ` ptomsich at gcc dot gnu.org 2022-04-26 0:05 ` christophm30 at gmail dot com 2022-04-26 8:12 ` cvs-commit at gcc dot gnu.org 2022-04-26 8:13 ` jakub at gcc dot gnu.org 2024-01-26 21:48 ` cvs-commit at gcc dot gnu.org
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